XTS Mil-Spec AR-15 Buffer Tube Assembly Kit, Black The XTS BTA-MIL buffer tube assembly groups five related AR-15 components in one black kit. A mil-spec buffer tube is supplied with a buffer, buffer spring, castle nut and end plate, giving shoppers an itemized package to compare with their requirements. The tube and associated components belong to the same listed assembly, which simplifies identifying the parts included in this purchase. The mil-spec tube designation is the key stock-interface reference. Matching the complete assembly to the intended rifle configuration remains important when selecting replacement components. Key Features Platform: AR-15 Tube designation: Mil-spec Package: Tube and associated assembly components Specifications Brand: XTS Model: XTS-BTA-MIL Color: Black Package Contents Buffer tube Buffer Buffer spring Castle nut End plate Shop the XTS Mil-Spec AR-15 Buffer Tube Assembly Kit, Black at BattleHawk Armory.